The purpose is to determine to what extent speech production can be altered in neurological disease by either behavioral manipulation or neuropharmacological treatment. One study was completed this year. The aim was to examine the relationship between speech rate, repetition rates and reaction times for the various articu-lators. Since reaction time tasks assess the initiation of a response by the articulators, the purpose was to determine whether speech rate was related to such reaction times in two different patient groups. If speech rate is related to articulator reaction times, then patients' speech rates may not be easily manipulated. Similarly, if the maximum rate of syllabale offset is related with speech rate, impaired speeds of movement offset could be a limiting factor on patients' abilities to change their speech rate. Patients with Parkinson's disease and Huntington's disease were studied. Both groups demonstrated a relationship between syllable offset time and speech rate indicating that movement offset time may be a limiting factor. Reaction time and speech rate were not related in either group. The Huntington's patients had slower reaction times than normal for speech movements requiring laryngeal and lip coordination and were excessively slow on all repetitive and speech rate measures. The Parkinson's patients were only affected on movements requiring rapid changes between laryngeal adduction and abduction. These results suggest that speech rate might be more easily manipulated in Parkinson's disease patients than in Huntington's disease patients.